Videogames Become a Spectator Sport

On any given day, Jayson Love fires up a personal computer from his Billings, Mont., home and starts his job—playing videogames in front of an audience of thousands.

The 33-year-old hosts a Web show called "MANvsGAME," in which he broadcasts his live gameplay on the site Twitch. Between advertising and subscribers paying $5 per month to watch his video stream, he says it is possible he'll earn more than $100,000 next...